CYIEnableSharedFromThis< YI_PTR_TYPE > Class Template Reference

Detailed Description

template<class YI_PTR_TYPE>
class CYIEnableSharedFromThis< YI_PTR_TYPE >

CYIEnableSharedFromThis<T> allows an object currently managed by a CYISharedPtr to safely generation additional CYISharedPtr internally.

Deprecated:

This class has been deprecated and may be removed in a future release. The std::enable_shared_from_this class should be used instead.

Consider the following example, which is going to result in a crash since your class instance may be managed by another mean, such as another shared pointer.

class MyClass
{
     CYISharedPtr<MyClass> GetManagedInstance()
     {
         return CYISharedPtr<MyClass> (this); // VERY BAD!
     }
}

MyClass pClass = new MyClass();

CYISharedPtr<MyClass> pSharedClass1(pClass);                        // pClass is now managed
CYISharedPtr<MyClass> pSharedClass2 = pClass->GetManagedInstance(); // DANGER: pClass is managed twice, separate reference count
...
pSharedClass1.Reset(); // reference count is decreased by one, and pClass is now deleted.
pSharedClass2.Reset(); // CRASH:  Double deletion.

This is where the CYIEnableSharedFromThis<T> comes into play. Inheriting from CYIEnableSharedFromThis<T> will provide convenient 'SharedFromThis()' function that will return a CYIWeakPtr<T> from the first CYISharedPtr<T> instance created. If the class is unmanaged by any CYISharedPtr<T>, 'SharedFromThis()' will return a null smart pointer.

class MyClass : CYIEnableSharedFromThis<MyClass>
{
     CYISharedPtr<MyClass> GetManagedInstance()
     {
         SharedFromThis(); // Safe.  Will return null if MyClass is unmanaged
     }
}

MyClass pClass = new MyClass();

CYISharedPtr<MyClass> pSharedClass1(pClass);                        // pClass is now managed
CYISharedPtr<MyClass> pSharedClass2 = pClass->GetManagedInstance(); // reference count from pSharedClass1 is now increased by one
...
pSharedClass1.Reset(); // reference count is decreased by one.
pSharedClass2.Reset(); // reference count is decreased by one, and pClass is now deleted.

Warning

Calling 'SharedFromThis()' on an unmanaged pointer will always return a null smart pointer.

Calling 'SharedFromThis()' from the Constructor will always return a null smart pointer.

#include <smartptr/YiEnableSharedFromThis.h>

Inheritance diagram for CYIEnableSharedFromThis< YI_PTR_TYPE >:

Protected Member Functions
CYISharedPtr< YI_PTR_TYPE >	SharedFromThis ()
	Returns a CYISharedPtr<T> which shares ownership of *this. More...
CYISharedPtr< YI_PTR_TYPE >	SharedFromThis () const
	Returns a CYISharedPtr<T> which shares ownership of *this. More...
	CYIEnableSharedFromThis ()
	CYIEnableSharedFromThis (const CYIEnableSharedFromThis &other)
	~CYIEnableSharedFromThis ()
CYIEnableSharedFromThis &	operator= (const CYIEnableSharedFromThis &other)

Constructor & Destructor Documentation

template<class YI_PTR_TYPE >

CYIEnableSharedFromThis< YI_PTR_TYPE >::CYIEnableSharedFromThis ( )

protected

template<class YI_PTR_TYPE >

CYIEnableSharedFromThis< YI_PTR_TYPE >::CYIEnableSharedFromThis ( const CYIEnableSharedFromThis< YI_PTR_TYPE > &  other )

protected

template<class YI_PTR_TYPE >

CYIEnableSharedFromThis< YI_PTR_TYPE >::~CYIEnableSharedFromThis ( )

protected

Member Function Documentation

template<class YI_PTR_TYPE >

CYIEnableSharedFromThis& CYIEnableSharedFromThis< YI_PTR_TYPE >::operator= ( const CYIEnableSharedFromThis< YI_PTR_TYPE > &  other )

protected

template<class YI_PTR_TYPE >

CYISharedPtr<YI_PTR_TYPE> CYIEnableSharedFromThis< YI_PTR_TYPE >::SharedFromThis ( )

protected

Returns a CYISharedPtr<T> which shares ownership of *this.

Warning

Will return null if the pointer is unmanaged.

template<class YI_PTR_TYPE >

CYISharedPtr<YI_PTR_TYPE> CYIEnableSharedFromThis< YI_PTR_TYPE >::SharedFromThis ( ) const

protected

Returns a CYISharedPtr<T> which shares ownership of *this.

Warning

Will return null if the pointer is unmanaged.

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The documentation for this class was generated from the following file:

• smartptr/YiEnableSharedFromThis.h